Worm for Myford Changewheels

[BazParticipant @baz89810]

[BazParticipant @baz89810]

Gentlemen, I wish to cut a worm about 1 inch diameter to mesh with a Myford changewheel. Can somebody please tell me what pitch(TPI) the worm would need to be, and also what angle tool would I need? I am making a loco building stand for Sweet Pea and want the worm drive to rotate the loco. The price of a commercial worm and wheel is enough to make your eyes water. Thanks in anticipation.

 

Baz

[KWILParticipant @kwil]

Myford gears are 20 DP.

[Engine BuilderParticipant @enginebuilder]

Bear in mind worm wheel teeth are cut at an angle to suit the worm. If you use a Myford change wheel the worm would need to be mounted at an ange and will not be  a perfect mesh. I have seen this is used in  homemade dividing attachments.

David

Edited By Engine Builder on 05/08/2010 12:59:29

[chris stephensParticipant @chrisstephens63393]

Hi Baz,

Do you have GHT’s book “The Model Engineers Workshop Manual”, if so check out his description of how it’s made.

Details can also be found in Radford’s  “Improvements & Accessories for your Lathe”

chriStephens 

[John Stevenson 1Participant @johnstevenson1]

To answer the original question you need a worm with a pitch of 6.366 TPI, the tools needs to have a 29 degree included angle and the change wheels to cut this are 55 driving 35 with a 40 driver on the 35 to a 50 on the leadscrew.

 

Do not disengage the half nuts but wind back every time.

 

John S.

[BazParticipant @baz89810]

Thank you all for your replies, I have more than enough information now to tackle the job, hopefully it will be done sometime over the weekend.

 

Baz

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